HRLEED and STM study of misoriented Si(100) with and without a Te overlayer

Abstract

The growth of high quality Te on misoriented Si(100) is important as an intermediate phase for epitaxial growth of CdTe. The misorientation angle plays a key role in the growth quality of CdTe/Si(100); this incited the curiosity to investigate the effect of the misorientation angle on the topography of the surface structure of Si(100). The main goal is to show the relation between the misorientation angle, the terrace width and the step height distributions. HRLEED (High Resolution Low Energy Electron Diffraction) provides information in reciprocal space while STM gives real space topographic images of the surface structure. STM and HRLEED measurements were performed on Si(100) with misorientation angle {var_theta} = 0.5{degree}, 1.5{degree} and 8{degree} towards the [110] direction and {var_theta} = 4{degree} towards the [130] direction. Except for the 8{degree} misorientation in which case a regular step array with diatomic step height was observed, for the other misorientations the terrace width was variable. The average terrace width decreased with increasing misorientation angle. A mixture of diatomic and monatomic step heights was observed on the 0.5{degree} and 1.5{degree} misoriented Si(100) samples. It proves that one can not assume purely monatomic step height for low misorientation angles. The results do not agree with the belief that at low miscut angle A and B terraces are equal and that as the misorientation angle increases the B terrace tends to be wider than the A terrace. In fact, pairing of terraces was not observed at all. Te was deposited at a substrate temperature of 200 C. The authors observed a significant reduction in the terrace widths for all miscut angles.